[MC-249431] The server occasionally fails to save chunks

The Bug:

The "Failed to save chunk" error is sometimes logged in the server console, thus indicating that the server occasionally fails to save chunks.

This issue was not present in 1.18.2 or 22w11a.

The following message was printed into the server console shortly after teleporting a far distance away and then running the "/kill" command. The full server log has also been attached which can be found below.

[^MC-249431 - Server Console Log.log]

[18:22:28] [Server thread/ERROR]: Failed to save chunk -16,-11
java.lang.NullPointerException: Cannot invoke "java.util.UUID.getMostSignificantBits()" because "$$0" is null
    at hi.a(SourceFile:27) ~[server-22w12a.jar:?]
    at hi.b(SourceFile:13) ~[server-22w12a.jar:?]
    at com.mojang.serialization.Encoder$1.encode(Encoder.java:25) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.Codec$2.encode(Codec.java:76) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.Encoder.encodeStart(Encoder.java:14) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.FieldEncoder.encode(FieldEncoder.java:24) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.MapCodec$1.encode(MapCodec.java:39) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.MapCodec$3.encode(MapCodec.java:181) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.RecordCodecBuilder$Instance$8.encode(RecordCodecBuilder.java:379) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.RecordCodecBuilder$2.encode(RecordCodecBuilder.java:112) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.MapCodec$MapCodecCodec.encode(MapCodec.java:96) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.Encoder.encodeStart(Encoder.java:14) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.OptionalFieldCodec.encode(OptionalFieldCodec.java:42) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.OptionalFieldCodec.encode(OptionalFieldCodec.java:17) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.RecordCodecBuilder$Instance$6.encode(RecordCodecBuilder.java:295) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.codecs.RecordCodecBuilder$2.encode(RecordCodecBuilder.java:112) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.MapCodec$MapCodecCodec.encode(MapCodec.java:96) ~[datafixerupper-4.1.27.jar:?]
    at com.mojang.serialization.Encoder.encodeStart(Encoder.java:14) ~[datafixerupper-4.1.27.jar:?]
    at cqe.b(SourceFile:51) ~[server-22w12a.jar:?]
    at cpf.o(SourceFile:84) ~[server-22w12a.jar:?]
    at cpf.m(SourceFile:64) ~[server-22w12a.jar:?]
    at cto.g(SourceFile:380) ~[server-22w12a.jar:?]
    at cuc.a(SourceFile:345) ~[server-22w12a.jar:?]
    at ads.a(SourceFile:828) ~[server-22w12a.jar:?]
    at ads.d(SourceFile:792) ~[server-22w12a.jar:?]
    at ads.b(SourceFile:531) ~[server-22w12a.jar:?]
    at ads.a(SourceFile:486) ~[server-22w12a.jar:?]
    at aed.a(SourceFile:326) ~[server-22w12a.jar:?]
    at aef.a(SourceFile:314) ~[server-22w12a.jar:?]
    at net.minecraft.server.MinecraftServer.b(SourceFile:903) ~[server-22w12a.jar:?]
    at adg.b(SourceFile:322) ~[server-22w12a.jar:?]
    at net.minecraft.server.MinecraftServer.a(SourceFile:847) ~[server-22w12a.jar:?]
    at net.minecraft.server.MinecraftServer.w(SourceFile:693) ~[server-22w12a.jar:?]
    at net.minecraft.server.MinecraftServer.a(SourceFile:271) ~[server-22w12a.jar:?]
    at java.lang.Thread.run(Thread.java:833) [?:?]

Steps to Reproduce:

Start a server running 22w12a.
Teleport a far distance away and then run the "/kill" command in order to make some chunks unload.

/tp @s ~10000 ~ ~

/kill @s

Respawn and watch the server console closely.
Take note as to whether or not the server occasionally fails to save chunks.

Observed Behavior:

The server fails to save chunks.

Expected Behavior:

The server would not fail to save chunks.

Linked issues

relates to

MC-275981 Server is constantly failing to save chunks

Attachments

MC-249431 - Server Console Log.log

Comments

MMK21 2022-03-25T17:24:46Z

According to MC-249444, it looks like this is also a chunk corruption bug, not just a logspam issue.

Avoma 2022-03-25T18:32:21Z

Thank you, I've updated this ticket accordingly. 🙂

Avoma 2022-04-06T13:21:02Z

This issue may have been fixed in 22w13a, although I'm not entirely sure so please don't take my word for it. After playing on a server running 22w13a for multiple hours and whilst exploring numerous amount of chunks during this time, this error was never logged in the server console.

Panda4994 2022-04-19T14:53:35Z

Can confirm, this has been fixed in 22w13a.

Avoma 2022-04-19T16:57:05Z

I thought it might have been; thank you!

Nicoder 2024-08-24T20:23:06Z

This bug still affects me on 1.21

[13:22:30] [IO-Worker-1940/ERROR]: Failed to save chunk 14,-1
java.util.concurrent.CompletionException: java.io.IOException: Operation timed out
at java.base/java.util.concurrent.CompletableFuture.encodeRelay(CompletableFuture.java:368) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.completeRelay(CompletableFuture.java:377) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$UniRelay.tryFire(CompletableFuture.java:1097) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:2194) ~[?:?]
at dwl.a(SourceFile:270) ~[server-1.21.jar:?]
at dwl.b(SourceFile:256) ~[server-1.21.jar:?]
at bpm$b.run(SourceFile:60) ~[server-1.21.jar:?]
at bpk.h(SourceFile:91) ~[server-1.21.jar:?]
at bpk.a(SourceFile:146) ~[server-1.21.jar:?]
at bpk.run(SourceFile:102) ~[server-1.21.jar:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]
Caused by: java.io.IOException: Operation timed out
at java.base/sun.nio.ch.UnixFileDispatcherImpl.pwrite0(Native Method) ~[?:?]
at java.base/sun.nio.ch.UnixFileDispatcherImpl.pwrite(UnixFileDispatcherImpl.java:71) ~[?:?]
at java.base/sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:135) ~[?:?]
at java.base/sun.nio.ch.IOUtil.write(IOUtil.java:102) ~[?:?]
at java.base/sun.nio.ch.IOUtil.write(IOUtil.java:72) ~[?:?]
at java.base/sun.nio.ch.FileChannelImpl.writeInternal(FileChannelImpl.java:1028) ~[?:?]
at java.base/sun.nio.ch.FileChannelImpl.write(FileChannelImpl.java:1012) ~[?:?]
at dwp.a(SourceFile:423) ~[server-1.21.jar:?]
at dwp$a.close(SourceFile:396) ~[server-1.21.jar:?]
at java.base/java.util.zip.DeflaterOutputStream.close(DeflaterOutputStream.java:249) ~[?:?]
at java.base/java.io.FilterOutputStream.close(FilterOutputStream.java:190) ~[?:?]
at java.base/java.io.FilterOutputStream.close(FilterOutputStream.java:190) ~[?:?]
at dwq.a(SourceFile:83) ~[server-1.21.jar:?]
at dwl.a(SourceFile:266) ~[server-1.21.jar:?]
... 8 more